Improvement in electric clocks



c. r. BRUSH.

ELECTRIC CLOCK.

No. 189,998. Patented ApriIH, 1877.

secon v Clock.

INVENTOR %A "a" .17 f l I ATTO Ys ILPEIERS, PHOTO-LITHOGRAPNEPL WASH UNITED STATES:

PATENT Cirrrcn CHARLES F. BRUSH, OF CLEVELAND, OHIO, ASSIGNOR OF ONE-HALF HIS RIGHT TO THE TELEGRAPH SUPPLY COMPANY, OF SAME PLACE.

IMPROVEMENT IN ELECTRIC CLOCKS.

Specifi cation forming part of Letters Patent No. 189,998, dated April 24, 1877; application filed August 28, 1876.

State of Ohio, have invented certain new and useful Improvements in Electrical Clocks; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it pertains to-make and use it, reference being had to the accompanying drawings, which form part of this specification.

My invention relates to an improvement in electrical clocks.

The object of the invention is to furnish a simple and reliable mechanism by which an electric current or circuit can be closed and opened at suitable regular intervals, for the purpose of operating one or more electric dials or secondary clocks included in said circuit. This mechanism I shall call, for convenience, the primary clock. It consists of a device or combination of devices for automatically closing and opening an electric circuit by means of a pendulum, actuated either by a weight or spring, and train of wheels, in the usual manner, or by an electro-magnet. The

occurs when the pendulum is near the middle of its are. The pendulum-rod, continuing to move to the right or left after the breaking of the circuit, encounters, near the completion of its are, a projecting pin and spring, which,

being moved thereby a short distance, raises the clutch above mentioned and releases the vertical arm, which, receiving motion by the falling of a small adjustable weight at tached to the secondlever mentioned, imparts, through a projecting pin at its lower end, an impulse to the pendulum during part of its receding movement. This impulse occurs every alternate second, and maintains the mo tion of the pendulum. At a convenient point on the pendulum-rod is attached a horizontal pin, which, at every vibration, engages with a small wheel or cam carried by a horizontal spring of weak tension, which latter is thus depressed sufficiently to touch a platinum point projecting upward from another weak horizontal spring. An electric circuit is thus established with but very little resistance to the motion of the pendulum. But it has been found by all electric-clock makers that when several electro magnets are included in a circuit carrying suflicient current to operate them, a spark occurs at the point of rupture of the circuit, due to what is technically knowr as the extra current. This spark rapidl destroys the metal surfaces where it occurs so that after a short time they begin to mis connection occasionally, thus making the clot, very unreliable. But the inventor has observed, during several years experience, that when the current to be closed and opened is of low electro-motive force, and operates only one or two small electro-magnets wound with coarse wire, no visible spark occurs at the point of rupture, the surfaces are not altered, and connection never fails from this cause. I therefore include in the circuit opened and closed by the pendulum, as above described, only one small electro-magnet, wound with coarse wire, and operated by a single cell of battery of low electro-motive force, such as a small Smee cell. This small magnet operates a relay differing from an ordinary relay in that the armature is placed on the longer end of a lever, the shorter end of which carries the platinum or gold contact-surface. This arrangement causes the surfaces to be brought together with more force than in the ordinary relay; still the latter may be used. The contact-surfaces are made quite broad so as to avoid rapid wear. In the electric circuit closed by the relay is included the magnet which moves the pendulum, and also those of all the secondary clocks to be run.

. Of course a spark occurs at the relay, at every rupture of the current 5 but thecontact surfaces, being large and moved with considerable force, are far less liable to miss connecspring 0.

' necessarily be very little, and the surfaces small accordingly. But the repeated occurrence of a spark would eventually render even the relay break-piece unreliable. I therefore connect each side of this break-piece with one -of the coatings of a condenser, such as is used with induction-coils, and consisting of large surfaces of tin-foil separated by sheets of varnished paper or other insulator. -The efiect of the condenser is the absorption of the spark exactly as is done at the break-piece-of an induction-coil. The spark is thus caused to disappear entirely, oris reduced to such small size and intensity as to be harmless. In stead of the condenser just described, a long fine metallic wire, or other conductor offering high electrical resistance, may be employed,

its ends being connected with the breakpiece in the same manner as the coatings of the condenser. In that case the extra current which is induced on breaking the circuit traverses the conductor of high resistance,

instead of producing a spark where the break occurs. The high resistance of the conductor affords a sufficient barrier to practically prevent the passage of the direct current.

If but a small number of secondary clocks are to be run by the primary one, the relay zontal arbor near the counter-weight, as

shown. This lever is raised by the attraction of the electro-magnet B when the latter is magnetized. c c are posts, with set-screws for regulating the movement of the lever A. Projecting downward and outward from the lever is the hook or pin a, which enables the latter to raise with it the second lever or arm 0, which is pivoted on an arbor at its other end. This lever is attached at its fulcrum to the vertical arm D, which has an offset at its lower end, as shown. E is a clutch or dog, having a horizontal arm, b, which falls into position and retains the arm D when the latter is thrown to the left by the action of the magnet B, and also'a vertical arm carrying at its lower end a projecting pin, 01, and weak These are shown in side elevation in Fig. 3, which also shows the arbor on which the clutch or dog is carried. The pendulumrod H is suspended from the clock Iin the usual manner.

The operation of the device is as follows:

.When the pendulum-rod swings toward the left and is at the middle of its stroke, the

magnet B will operate, as will be hereinafter shown, and the arm D will be thrown to the left,as indicated; but the magnet very soon releases its armature, owing to the rupture of the electric current, and the lever A falls. The arm .D, however, being retained by the clutch E at I), does not move. The pendulumrod, continuing to move toward the left, encounters the light spring e, which is depressed until it (the rod) touches the pin (1, projecting from the arm E. This moves the arm to the left, and releases the clutch at b, which is then thrown upward by the recoil of the spring c. This arrangement prevents the sudden resistance that would be offered to the pendulum by striking the pin (1, and-requiring the friction at b to be instantly overcome, and substitutes therefor the gradual resistance of the spring, which resistance gradually overcomes this friction at b, and distributes the'resistance against the pendulum over a considerable length of its stroke. The pin (1 is to protect the spring 0 and raise the clutch, should the spring prove inadequate.

When the rod finally stops and starts back toward the right, it is urged forward by the pin l, which is actuated by the weight m on the lever O. The pin follows the rod farther than it was lifted by the latter, because the clutch-arm I), being held out of the way by the spring 6, allows the arm D to move past m to the right or left on the lever which carries it.

At the lower part of the drawing will be seen the electric-circuit break-piece, which isoperated by the pin a on the pendulum-rod.

The rod is cut away for the accommodation of the break-piece, as shown in Fig. 2. This break-piece consists of a small wheel or cam, 0, carried by a weak spring, 9, which is attached to the post 7'. At the other end of the spring, on its lower side, is a small platinum or gold plate. (Not shown.) Another similar spring, t, is attached to the post 8, and has a platinum'or gold Wire, 0, attached near its free end, and projecting upward so as to touch the platinum or gold plate carried by 1) when the latter is slightly depressed. This occurs when the pin it on the pendulum-rod passes the wheel or cam 0. :1; represents screws for adjusting the springs 11 and t, both with ref erence to each other and to the pin to. In this way the length of contact may be varied at pleasure, but should be made short to econothe pendulum-rod, and the pin to thespring;

or the motion imparted by the pendulum-rod may be upward instead of downward.

In the circuit closed by this break-piece are the electro-magnet N and a small battery, as shown.

The magnet N operates an armature attached to the lever M, which has its fulcrum at 3 At the other end of the lever is attached a piece of platinum or gold, opposite the platinum or gold end of a set-screw, g. g is another set-screw for regulating the movement of the lever. The parts form the relay or second break-piece referred to. Inits circuit are included the magnet B, the secondary clocks, and larger battery, as shown. The drawing also shows how the condenser is attached, for the purpose of absorbing the spark which would otherwise occur at the point 2 at every "rupture of the current.

By means of these simple devices an exceedingly accurate and reliable primary electric clock is formed.

I desire it to be distinctly understood that by the term condenser in the claim I mean any device, such as a Leyden jar, or series of surfaces, or wire, or other device, whereby the extra current is absorbed or discharged, as hereinbef'ore described.

iWhat I claim as my invention, and desire to-secure by Letters Patent, is-

1. The pendulum-actuating lever, in combination witIr t-he clutch or dog E, provided with springs e and pin d, substantially as and for the purpose described.

2. The combination, with the pendulum, of the angular pendulum-actuating lever O D, and angular clutch E, and spring 0, substantially as and for the purpose described.

3. The clutch or dogE, provided with spring 6 and pin d, substantially as and for the purpose described.

4. In an electrical clock, the combination, with a magnet and armature-lever, of adjusting mechanism and contact-surfaces z, the latter carried on the shorter arm of the armature-lever, and the whole constituting the relay, substantially as and for the purpose described.

5. The combination of the relay, pendulum H, break-piece, and a battery of low electromotive power, substantially as and for the purpose described.

6. In an electrical clock, the combination, with arelay, of a condenser and main battery, substantially as set forth.

7. In an electrical clock, the combination, with relay, of a condenser and secondary clocks, substantially as and for the purpose described.

8. The combination of a light battery-circuit, embracing break-piece and relay, with a batterycircuit embracing condenser, secondary clocks, and electro-magnets B, said magnets B operating, through intermediate mechanism, to vibrate the pendulum H, substantially as and for the purpose described.

9. The combination of a light battery-circuit, embracing break-piece and relay, with a battery-circuit embracing condenser and secondary clocks, said light battery-circuit made or broken by the vibration of the pendulum H, substantially as and for the purpose described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

CHARLES F. BRUSH.

Witnesses FRANCIS Tour/my, JAMES P. WALSH. 

